This application claims the priority of European Application No. 01114113.2 filed Jun. 9, 2001, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a pressure die casting machine for processing fused metals that has a machine tool table having arranged on it a casting nozzle and a die locking unit that can be aligned with the nozzle and is comprised of a crosshead, a stationary die platen and a die platen that is mounted on a guide pillar and can be moved to press against the stationary one and is mounted with a high degree of adjustability on an inclined guide surface that is supported on the machine tool table.
A pressure die casting machine of this type is known from German Patent 30 18 288 A1 (corresponds to U.S. Pat. No. 4,566,522). In that case, the die locking unit is mounted on guide rails that are inclined in relation to the horizontal guide rails. Since different gate positions are provided on the die, depending on the type of die to be used, it is necessary to adjust the height of the locking part. With hot-chamber pressure die casting machines, the casting nozzle, because the casting container always remains in the molten mass, is generally known to stay in a particular position, so that the gating part of the die must be adapted to this casting nozzle.
To adjust height in this case, levers, which are mounted crosswise in relation to each other and form a scissors mechanism that engages beneath the locking unit on the bottom of the crosshead and the movable die platen and can be spread from each other via a drive mechanism, are provided in the known hot-chamber pressure die casting machine. Such a configuration takes up a relatively large amount of space beneath the locking unit. Depending on the die locking part position and the load distribution required as a result, even an exact synchronous running is not always ensured with a design of this type.
Known from German Patent 34 23 056 C2 is a height adjustment device for the die locking unit of a hot-chamber pressure die casting machine in which one pressure cylinder has been assigned to the crosshead and a second pressure cylinder arrangement has been provided on the stationary die platen and the two pressure cylinders are each propped against the machine tool table. Due to the joint pressure medium action for the two pressure cylinder mechanisms, the die locking unit can also be adjusted in height. However, this design is relatively expensive because the pressure means circuit must be controlled exactly via appropriate relay valves.
An object of the present invention is therefore to develop a hot-chamber pressure die casting machine of the type mentioned at the beginning such that a simple height adjustment attainable with mechanical elements alone becomes possible, which has a simple and space-saving design.
This objective is achieved with a pressure die casting machine of the type mentioned at the beginning by providing that the inclined guide surface part provided there is part of a lifting frame that is mounted in a vertically adjustable way on the machine tool table. This configuration now makes it possible in a simple manner to move the entire lifting frame in parallel and vertical senses. In a further development of certain preferred embodiments of the invention it is facilitated in an especially simple manner for the lifting frame to be adjustable using at least two pairs of levers that are arranged in the manner of a parallelogram which can be swiveled in the same direction. Thus, one lever pair each can be assigned to the lifting frame approximately in the areas of the two ends of the lifting frame so that, if a common drive mechanism is provided for the lever pair, an exactly parallel raising of the lifting frame is achieved.
In this context, in a further development of certain preferred embodiments of the invention, a mechanical connection between the lever pair having a drive mechanism acting in the direction of the connection can be provided in a very simple manner as a common drive mechanism. In a simple configuration, the lever pairs can be designed as two lever sets connected by a joint to an elbow lever pair, of which one lever is pivot-mounted on the lifting frame and the other is mounted on the machine tool table. The common drive mechanism in this case engages in the connection joint of both levers. A connecting rod or even a gear rack can be provided in a simple manner as a common drive mechanism, whereby an electric motor with a gearbox, for example, can be used as the drive mechanism. Obviously, a hydraulic motor, a hydraulic cylinder or a pneumatic bellows-type cylinder can also be provided as the drive mechanism. Even a hand crank, a linear motor or an eccentric crank drive or a so-called pneumatic muscle can be provided as a drive mechanism. In any case, a mechanical element, thus for example a connecting rod, is pushed by the drive mechanism, which then actuates the two elbow lever pairs jointly so that an exact synchronous operation to raise the lifting frame, and with it the die locking unit, is ensured. Complicated controllers are not necessary. Since this lever drive can be integrated in the lifting frame, no additional space is needed for the arrangement of a separate lifting device.
The precondition for these mechanically effected vertical lifting movement is vertical guides for the lifting frame, which can be designed, for example, as stationary vertically running pins or rails on the machine tool table that engage in guides of the lifting frame or vice-versa.
Guide pins or rails project from the lifting frame and are conducted into corresponding vertical guides of the machine tool table.
The invention is illustrated on the basis of an embodiment and explained below.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.